Terephthalic acid (TPA) and its esters and derivatives are important precursors for the synthesis of polyesters and other useful materials.
The largest use of TPA at present is production of polyesters. For example, TPA is used to produce polyethylene terephthalate (PET) which is used extensively in consumer goods packaging, most prominently in the now ubiquitous plastic water bottles. TPA is produced on the scale of many millions of tons per year scale by oxidation of xylenes which are obtained from petroleum distillates.
There is strong demand from consumers and consumer goods companies for sustainable alternatives to petroleum-based plastics for packaging applications. Indeed, Coca Cola® and others have recently introduced PET containing biobased monoethylene glycol (MEG). Beverage bottles made from this PET are branded as the “Plant Bottle™” and have been well received in the marketplace. Unfortunately, since about 70% of the mass (and 80% of the carbon atoms) in PET derives from terephthalic and isophthalic acids, replacing petroleum-sourced MEG with biobased material yields PET that is only about 30% biobased and contains only 20% renewable carbon. There is huge interest in biobased IPA and TPA to enable fully biobased PET production, but to date no economically feasible biobased processes exist.
Polystyrene is another polymer that is derived from petroleum feedstocks and utilized on huge scale (billions of kgs per year). To make matters worse, polystyrene is not widely recycled and is therefore a large contributor to litter and landfill waste. At present there is no bio-based polystyrene available to consumer goods companies.
The present invention solves this problem and others related thereto.